The following paper was published recently: Mansourian, Y. (2008). Web search efficacy: definition and implementation, Aslib Proceedings , Vol. 60, No. 4, pp. 349-363. Abstract: Purpose – This paper aims to report a number of factors that are perceived by web users as influential elements in their search procedure. The paper introduces a new conceptual measure called “web search efficacy” (hereafter WSE) to evaluate the performance of searches mainly based on users' perceptions. Design/methodology/approach – A rich dataset of a wider study was inductively re-explored to identify different categories that are perceived influential by web users on the final outcome of their searches. A selective review of the literature was carried out to discover to what extent previous research supports the findings of the current study. Findings – The analysis of the dataset led to the identification of five categories of influential factors. Within each group different factors have been recognize